Glucose-based highly-porous activated carbon nanospheres (g-ACNSs) for high capacity hydrogen storage

Abstract

Nanoporous glucose-based active carbon nanospheres (g-ACNSs) with high efficiency and stability in hydrogen (H₂) storage are synthesized by a hydrothermal method followed by multiple KOH activation processes. For the optimized conditions (g-ACNS24), they exhibit a high specific surface area of 2291 m² g⁻¹ and a large defect ratio (I_D/I_G = 1.77) in the carbon structure. With these structure characteristics, the g-ACNS24 demonstrates an H₂ storage capacity of 5.04 wt% and a high hydrogen uptake capacity (>80%) in the durability test for more than 100 storage cycles at 77 K and 100 bar. DFT calculation results show that the chemisorption hydrogen adsorption enhances in an amorphous model with mixed coordinated carbon atoms compared to a perfect six-membered graphene surface. This once again proves that the superior hydrogen storage performance of g-ACNSs can be attributed not only to their high specific surface area and large pore volume, but also to the distribution ratio of micropores and associated defects. Overall, the findings suggest that g-ACNS materials hold promise as efficient and cyclically stable materials for hydrogen storage, with potential applications in the field of hydrogen energy.